As trains travel into and through tunnels, they compress the air in front and create powerful pressure waves. Known as the piston effect, the phenomenon is a key consideration for engineers, with implications for aerodynamics, ventilation and noise pollution – but for a group at the University of Manchester, it could provide an unlikely source of low-carbon energy.
Announced last week (22 October), the new project aims to harness the airflow generated by trains by installing wind turbines at tunnel exits. And while an expert told Professional Engineering that such systems would likely struggle to compete with solar cells, the Manchester researchers hope to provide useful amounts of energy by using the correct combinations of turbine design and placement.
Those factors will be determined using a bespoke toolkit to evaluate the performance and commercial viability of potential systems, allowing engineers to test and scale different designs of vertical-axis wind turbines. Known as VerXis Wind, the toolkit includes a library of designs that can be tailored for different tunnels, including adjustable parameters such as rotor diameter and height, number of blades and turbine spacing.